Varieties of generalization inspired by Pavlov's legacy.

In this selective review, we summarise recent studies from our laboratory in which we have assessed the effect of different variables (such as contiguity and contingency) on the generalization of prior learning. Much of this work was inspired by Pavlov's work in which it was first documented that trace conditioning can broaden generalization, a finding that we have replicated in human participants. We then describe studies in which we have assessed whether the affective valence of stimuli and outcomes can affect generalization, and we find that indeed human participants can generalize across the valence of stimuli and this can interact with different outcomes. Finally, we review a study in which we assessed whether changes in a response-produced safety signal can influence avoidance and conclude that it does. We also observed that this generalizes depending on the similarity between trained and tested safety signals (i.e., outcomes). Overall, we conclude that generalization is a much more complex phenomenon than previously thought, and that more research is needed to understand this phenomenon and make it amenable to current theorising.